Rotating vibrator

ABSTRACT

A vibrator has two rotating eccentric masses which are interlocked to operate at the same speed. The eccentric masses are arranged so that one is movable circumferentially during rotation relative to the other to change between a vibrating condition and a non-vibrating condition. Two individual motors may be utilized to drive the eccentric masses, and means are provided for changing the relative torque outputs of the motors to shift one eccentric mass relative to the other to change between the vibrating condition and the non-vibrating condition.

United States Patent- Gaylord I 1451 June 20, 1972 [s41 ROTATINGVIBRATOR 3,385,119 5/1968 Berger a ..94/43 x Inventor: Richard P.Gaylord,- SL jdscph, Mich 3,543,656 12/1970 Roettger ..94/50 V [73]Assignee: Clark Equipment Company Primary Examinere-Jacob L. Nackenofi IY Attorney-Kenneth C. Witt, John C. Wiessler, Robert H. Filed: DEC- 28,Johnson Lamm [211 App]. No.: 101,892

7 [57] ABSTRACT [52] U.s. Cl. ..94/50 V, 74/61 A vibrator has two o g nric m es which are inter- 51 Int. Cl. ..Elc 19/28 Opera" 58 Field 61Search ..94/50 50 v- 74/61 87 man! that is mdvabl ci'cumfmmially durinltion relative to the other to change between a vibrating condi- [56]Rehrences Cited tion and a non-vibrating condition. Two individualmotors I may be utilized todrive the eccentric masses, and means areUNITED STATES PATENTS provided for changing the relative torque outputsof the mo- 7 tors to shift one eccentric mass relative to the other tochange 3,498,601 3/ i970 Koval ..74/6l X between the vibrating conditionand the nonwibrating condi 3,262,329 7/1966 Herrmannm; ...94/48 X on.3,505,885 4/1970 Waschulewski.... ..;94/48 X 7: 3,192,839 :7/1965 Viviet.l "94/50 V 7 Claims, 7 Drawing Figures 36 as 3e 40 44, a 28 PATENTEDJumm2 I 3.670.631

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IN TOR RICHARD P. LORD XMG z/gzt ATTORNEY ROTATING VIBRATOR BACKGROUNDOF THE INVENTION This invention relates to rotating vibrators which canbe changed during rotation between one condition in which vibrationoccurs and another condition in which the vibration does not occur, orat least is of a lower magnitude. The rotating vibrator disclosed hereinis particularly useful in vibratory vehicles which are used to compactbituminous paving materials, crushed rock, earth and other materials,but it will be recognized that it is not limited to such use.

Various types of vibrators are known and used in vehicles which areemployed in compacting bituminous paving materials, crushed rock, earthand other materials, and one is the rotating type. One difficulty withthe use of rotating vibrators in such compactor vehicles heretofore hasbeen that when it is necessary to stop the compactor vehicle onbituminous paving material, for example, that it is necessary to stop orat least slow down the rotating vibrator to prevent the roller of thevibrator vehicle from producing an unwanted depression at the placewhere the roller stops. It will be appreciated this is a considerableproblem when a vibratory roller vehicle is being utilized for compactingmaterial such as paving material, because the rolling normally is donein a continuing back and forth operation.

Accentuating the problem is the fact that in many rotating vibrators,when the eccentric mass is slowed down, the entire rotating system goesthrough a critical speed at which a resonant condition of the variouselements of the system produces a vibration that actually becomesgreater for a brief period. Some times it is so great that it isdeleterious to the compact or vehicle as well as unpleasant to theoperator.

The present invention provides a construction which makes it readilypossible to stop the vibrating action of the rotating vibrator at anytime that the operator desires to do this, and then to resume vibratingaction quickly at the wish of the operator.

SUMMARY OF THEINVENTION In carrying out my invention in one form, Iprovide a vibrator having two rotating eccentric masses which areinterlocked to operate at the same speed. One of the eccentric masses isarranged so that it is movable circumferentially during rotationapproximately 180 relative to the other to change from a condition inwhich the offset masses of the eccentrics are additive and vibration isproduced to a condition in which the offset masses counteract each otherand vibration is stopped. Means are provided for driving the eccentricsindividually and for changing the relative torque outputs of theindividual driving means to move oneeccentric between two positions toshift between the vibrating condition and the nonvibrating condition. 1

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a side elevational view ofa vibratory roller vehicle embodying the present invention;

FIG. 2 shows a front end view of the same vehicle;

FIG. 3 shows a sectional view along the line 3-3 of FIG. 1;

FIG. 3A shows a fragmentary sectional view along the line 3A-3A of FIG.3;

FIG. 4 shows a fragmentary sectional view along line 4-4 of FIG. 3(inside left cylinder member 36);

FIG. 5 shows another fragmentary sectional view along line 4-4 of FIG.3; and

FIG. 6 shows a schematic diagram of the hydraulic circuit which may beused to operate the two hydraulic motors forming a part of the disclosedvibrator.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIG. 1 of the drawing,there is shown a compactor vehicle 10 which embodies the presentinvention. The vehicle 10, in addition to the main body portion 12,includes a pair of rubber tired rear wheels 14 (only one of which isvisible in the drawing) and a single cylindrical metal roller 16 at thefront of the vehicle. In the vehicle illustrated, only the wheels 14 aredriven and this is accomplished in the usual manner by means of anengine within enclosure 18 which, through a suitable transmission andaxle, drives the rear wheels 14. The front drum or roller 16 rollsfreely as the vehicle moves forwardly or rearwardly; however, roller 16contains a vibrator therein which is illustrated in the drawing anddescribed in detail hereinafter. The vehicle 10 includes the usualoperator's station including a seat 20, an operator's steering wheel 22,and the other devices necessary for the operation of vehicle 10.

The vehicle illustrated is of the articulated type. For steering, it isarranged so that the front roller of the vehicle and the rear portion ofthe vehicle supported by the two rubber tired wheels may be pivoted withrespect to each other about a vertically disposed axis 24 in a knownmanner. The vehicle illus trated also is arranged so that the roller 16is arranged to pivot from side to side about a longitudinally disposedaxis 26, to accommodate unevenness in the ground or pavement over whichthe compactor vehicle 10 is operating.

The roller 16 is supported on a pair of structural members 28, one oneach side of the roller, as best seen in FIG. 2, and at the front of theroller, a cleaner member 30 may be provided.

As mentioned previously, roller 16 rolls freely as the vehicle ispropelled by the driving wheels 14, and the structure by which this isaccomplished is illustrated in the sectional view of FIG. 3. As shown inFIG. 3, the roller16 comprises an outer cylindrical member 32. Extendinginwardly from member 32 are structural members 34 adjacent both ends of32 which are connected respectively to cylindrical members 36, which inturn are connected by means of intermediate members 38 to outwardlyprojecting bearing support members .40. Extending inwardly within therotatable members 40 are integral cylindrical portions 42 of structuralmembers 44 which are, in turn, secured to the structural members 28extending along both sides of the roller 16 by intervening spacers 29and rubber vibration isolators 31. See FIG. 3A in addition to FIG. 3 forthe details of this structure. As shown, rotatable portions 40 arecarried on fixed portions 42 by means of tapered roller bearings 46.

As illustrated and described herein, roller 16 houses a double vibrator,but it will be readily appreciated by those skilled in the art that thepresent invention is equally applicable to a single vibrator or it caninclude more: than two vibrators. Inasmuch as the. two vibrators shownare the same except that one is allochirally related to the other,thesame identifying numerals and description are given for both.

Each of the two vibrators is indicated generally by the numeral 48 andeach comprises an outer eccentric portion or member 50 and an innereccentric member 52, although it will be understood that the presentinvention is not limited to having one of the vibrator members housedwithin the other.

It should also be understood that where reference is made hereinafter inthe claims and elsewhere to the term eccentric that the intention is torefer to a member or structure which has a center of mass which is notlocated at the center of rotation of the member or structure. The shapeof the member will ordinarily be nonsymmetrical with respect to the axisof rotation, but regardless of the shape, the essential feature in thisinvention when reference is made to an eccentric is that the center ofmass does not coincide with the center of rotation.

In the preferred mode of carrying out the invention described andillustrated herein, the inner eccentrics 52 are driven by means of ahydraulic motor 54 which appears at the left of FIG. 3. Motor 54 drivesboth of the innereccentrics 52 through universal joints 56, a shaft 58connecting with the eccentric 52 on the left and another shaft 60connecting the two inner eccentrics together for conjoint rotation.

The outer eccentrics 50 in this compactor vehicle are driven by anotherhydraulic motor 62 which appears at the right in FIG. 3 throughuniversal joints 64 which connect to the outer eccentric 50 on theright, and a hollow shaft 66 which connects the two outer eccentricmembers 50 together for conjoint rotation. The necessary bearings,seals, connections and other parts are provided for the motors and theeccentrics and other parts driven by the motors.

FIG. 4 of the drawing shows the configurations of the eccentric 52. Itscenter of mass is considerably below the axis of rotation 61 (the axisof shaft 60) with the result that vibration is produced when eccentric52 is rotated. Also appearing in FIG. 4 is a projection 68 from theinside surface of the outer eccentric 50, by which the two eccentricsare interlocked, and in the position shown, projection 68 abutseccentric member 52 at 70. When the two eccentric members are in thisposition, their centers of mass are both on the same side of the axis ofrotation. It is pointed out that outer eccentric member 50 hasprojections 72 at the bottom (see FIG. 3) which increase the weight ofthe bottom portion of this member in the position indicated in FIG. 3 ofthe drawing. Thus, if the two eccentrics are rotated by their respectivehydraulic motors and they remain in the relative circumferentialrelation shown in FIG. 4, vibration will be produced which reacts uponthe drum member 16. It will be appreciated that the vibrator on theright side of FIG. 3 operates in the same manner as the vibrator on theleft side.

If it is desired quickly to stop the vibration it is necessary only toaccomplish the movement of the outer eccentric members 50circumferentially 180 with respect to the inner eccentric members 52 tothe position illustrated by the dot-dash lines in FIG. 4 and indicatedby the identifying character 68'. This can be done very readily andquickly with the present invention, and the manner in which it isaccomplished will be understood by reference to FIG. 6 of the drawing.

FIG. 6 shows the hydraulic circuit for operating the hydraulic motors 54and 62 to rotate the eccentrics 52 and 50 respectively. The hydraulicsystem comprises a pump 74 which draws fluid from a reservoir 76 anddischarges it under pressure through a valve 78, through a conduit 80,and thence through motors 62 and 54. The flow of pressurized fluid fromconduit 80 is divided approximately equally by a pair of orifices 82 and84 which are in circuit with the respective motors on the dischargeside. It will be appreciated that if these orifices were preciselyequal, and both motors and their loads were identical, that both motorswould operate at exactly the same speed. As a practical matter, however,only an approximation of equal flow is required and a slight inequalityin the flow between the two orifices is not critical. The flow throughmotor 62 drives the outer eccentrics, while the flow through motor 54drives the inner eccentrics 52. From the respective hydraulic orifices82 and 84 the fluid is returned through conduits 86 and 88 back to thereservoir. Valve 78 preferably is of the open-center type and whenoperation of neither of the motors is required, it bypasses fluid bymeans of conduit 90 directly to 88 and thence back to the reservoir.

During operation, when vibration is desired, assuming that pump 74 is inoperation and that valve 78 is open, a valve 94 is opened which is inparallel with orifice 84. Valve 94 then passes a small additional amountof fluid to make certain that motor 54 exerts more torque than motor 62and that inner eccentric 52 abuts projection 68 on the outer eccentricas shown in FIG. 4. Arrow 7] in FIG. 4 shows the direction of rotation.This causes the two eccentrics of each pair to assume the additive orvibrating position illustrated in FIGS. 3 and 4. When it is desired toneutralize the vibration, valve 94 is closed and valve 92 is opened toprovide additional flow to motor 62. This causes the outer eccentrics 50to overtake the inner eccentrics 52 and the projection 68' on the outereccentrics to move 180 so that the eccentrics 50 in each case push oneccentrics 52 instead of vice versa, and in this position, the effectsof the off-center masses of the inner and outer eccentrics cancel eachother and there is no vibration. The letter condition is illustrated bythe dot-dash lines of projection 68' in FIG. 4.

It will be understood by those skilled in the art that the location oforifices 82 and 84 and valves 92 and 94 on the discharge side of themotor prevents the possibility of cavitation in the motors and assures amore positive control than if the orifices and valves were located onthe inlet side.

It will be appreciated that the operation described in the precedingparagraph is dependent upon pressure as to which motor is dominant. Thatis, if valve 94 is open and 92 is closed, there is a lightly lesspressure drop through the combination of valve 94 and orifice 84 thanthrough orifice 82 which produces slightly greater pressure drop acrossmotor 54 than across motor 62 and thus causes motor 54 to exert aslightly greater torque than motor 62. The reverse is true, of course,when valve 92 is open and valve 94 is closed.

It will be appreciated also that it is possible to utilize flow insteadof pressure to control the motors 54 and 62 and this makes it possibleto control the relative circumferential position of the two eccentricsso that they may be positioned at any of an infinite number of positionsbetween the two extreme positions illustrated in FIG. 4. For example,FIG. 5 shows the outer eccentric 50 rotated so that it is approximatelyhalf way between the extreme positions of FIG. 4, and in this position,the stop portion is indicated by the character 68". By adjustment of theflow through valve 94 or valve 92 or both, it is possible to achieve anydesired intermediate position; and, of course, the amount of vibration,assuming the speed of rotation remains the same, is reduced as the outereccentric 50 moves circumferentially relative to eccentric 52 from thesolid line position of stop member 68 as shown in FIG. 4 to the dot-dashline position 68' of such stop member. Thus, the present invention canbe utilized not only to start and stop vibration, but also to adjust itas desired between maximum vibration and no vibration.

Referring again to the on-off operation first described, it will bereadily appreciated that if desired, valves 92 and 94 can be connectedto the shifting mechanism of the vehicle so that whenever thetransmission of the vehicle is shifted to neutral, valve 94 is closedand valve 92 opened to cause vibration to stop. Under other conditions,when the vehicle is moving forwardly or rearwardly, valve 92 is closedand valve 94 is open, and under such conditions the vibrators are bothin full operation.

It will be appreciated also that is may not be necessary to use bothvalves 92 and 94. The orifices 82 and 84 can be unbalanced slightly sothat one motor normally will dominate over the other. For example,orifice 82 could be made larger so that motor 62 will normally dominateand this makes unnecessary valve 92. Under these circumstances, onlyvalve 94 is used, and it is made large enough that in combination withthe flow through orifice 84, it causes motor 54 to dominate over motor62.

.While I have described and illustrated herein a preferred form of myvibrator and a vehicle in which it can be used, it will be understoodthat modifications may be made in both the vibrator and the vehicle. Forexample, electric motors or pneumatic motors can be used instead ofhydraulic motors or mechanical drives from the engine propelling thevehicle providing only that the operating or driving means for the twoeccentrics are separately controllable. Accordingly, it should beunderstood that I intend to cover by the appended claims all suchmodifications falling within the true spirit and scope of my invention.

I claim:

1. A vibrator having two rotatable eccentrics which are interlocked tooperate at the same speed, the eccentrics being arranged so that theyare movable circumferentially relative to each other during rotation tochange the location of the center of mass and thereby the amount ofvibration, separate means driving the said eccentrics respectively, andmeans for changing during rotation the driving force of one of the saidseparate driving means relative to the other.

2. A vibrator as specified in claim 1 in which one of the saideccentrics is in the form of a housing which houses the other saideccentric and the said eccentrics rotate in the same direction.

3. A vibrator as specified in claim 2 in which there is an inwardprojection from the said housing which abuts the inner eccentric andpermits approximately 180 relative movement between the two eccentrics.

4. A vibrator as specified in claim 1 in which the said separate drivingmeans are two hydraulic motors, and includ ing means for causing eitherof the said motors selectively to exert more torque than the other.

5. A vibrator as specified in claim 4 which includes a single source ofpressurized fluid for the two hydraulic motors, a flow divider fordividing the flow from such source approximately equally between themotors, and a valve arranged in parallel with one of the flow dividerswhich when it is opened unbalances the fluid flow through the motors.

6. A vibratory compactor comprising a horizontally disposed cylindricalroller containing two rotatable eccentrics which are interlocked tooperate at the same speed, the eccentries being arranged so that oneeccentric is movable during rotation of the eccentrics circumferentiallyapproximately relative to the other to change between a condition inwhich the offset masses of the eccentrics are additive at least in partand vibration of the roller is produced and a condition in which theoffset masses at least partially counteract each other and there is lessor no vibration, two motors located respectively adjacent the oppositeends of the roller and connected respectively for driving the saideccentrics, and means for changing the relative driving forces of thesaid motors to move the said one eccentric to achieve the desired amountof vibration.

7. A vibratory compactor as specified in claim 6 having a second pair ofrotating eccentrics, each of the said pairs of eccentrics including anouter eccentric and an inner eccentric, the two outer eccentrics beingconnected together and driven by one of the said motors, and the twoinner eccentrics connected together and driven by the other of the saidmotors.

1. A vibrator having two rotatable eccentrics which are interlocked tooperate at the same speed, the eccentrics being arranged so that theyare movable circumferentially relative to each other during rotation tochange the location of the center of mass and thereby the amount ofvibration, separate means driving the said eccentrics respectively, andmeans for changing during rotation the driving force of one of the saidseparate driving means relative to the other.
 2. A vibrator as specifiedin claim 1 in which one of the said eccentrics is in the form of ahousing which houses the other said eccentric and the said eccentricsrotate in the same direction.
 3. A vibrator as specified in claim 2 inwhich there is an inward projection from the said housing which abutsthe inner eccentric and permits approximately 180* relative movementbetween the two eccentrics.
 4. A vibrator as specified in claim 1 inwhich the said separate driving means are two hydraulic motors, andincluding means for causing either of the said motors selectively toexert more torque than the other.
 5. A vibrator as specified in claim 4which includes a single source of pressurized fluid for the twohydraulic motors, a flow divider for dividing the flow from such sourceapproximately equally between the motors, and a valve arranged inparallel with one of the flow dividers which when it is openedunbalances the fluid flow through the motors.
 6. A vibratory compactorcomprising a horizontally disposed cylindrical roller containing tworotatable eccentrics which are interlocked to operate at the same speed,the eccentrics being arranged so that one eccentric is movable duringrotation of the eccentrics circumferentially approximately 180* relativeto the other to change between a condition in which the offset masses ofthe eccentrics are additive at least in part and vibration of the rolleris produced and a condition in which the offset masses at leastpartially counteract each other and there is less or no vibration, twomotors located respectively adjacent the opposite ends of the roller andconnected respectively for driving the said eccentrics, and means forchanging the relative driving forces of the said motors to move the saidone eccentric to achieve the desired amount of vibration.
 7. A vibratorycompactor as specified in claim 6 having a second pair of rotatingeccentrics, each of the said pairs of eccentrics including an outereccentric and an inner eccentric, the two outer eccentrics beingconnected together and driven by one of the said motors, and the twoinner eccentrics connected together and driven by the other of the saidmotors.